Making a start up disc in Dos question?

I need to flash the graphics card that I got from gigabyte and the only way to do it is in dos mode. I have never really done this before so please give me some info. I will extract the downloaded zip to my hard disk, then restart my computer in dos mode but in xp I must use a start up disc it says. I need to change the command prompt to C:\> and then begin to flash the bios by typing atiflash -p 0 filename then it says example (r955128d.f1 at the c prompt and press enter then restart. I am not sure how to make the start up disc in dos and really what to do in the command prompt. Any help will be greatly appreciated.